Concrete form assembly having expandable inner core

ABSTRACT

A form assembly for prefabricating a concrete structure by casting that includes an outer member and an inner member between which a cavity is defined, the inner member having expandable walls that are urged outwardly by jack elements and that are releasable to provide for removal of the inner and outer members after the structure is cast and is still curing in place.

United States Patent [191 Messier CONCRETE FORM ASSEMBLY HAVING EXPANDABLE INNER CORE [76] Inventor: Albert J. Messier, Mendon St.,

Blackstone, Mass. 01504 [22] Filed: June 21, 1971 [21] Appl. No.: 154,919

[52] US. Cl 249/14, 249/63, 249/122, 249/142, 249/180, 249/184 [51] Int. Cl B28b 7/22 [58] Field ofSearch 249/14, 119, 122, 249/63, 127, 178, 179, 180, 183, 184, 182,

[56] References Cited UNITED STATES PATENTS 3,074,140 1/1963 Balcomb et a1 249/183 X 11] 3,780,976 1 Dec. 25, 1973 3,281,110 10/1966 Lister 249/14 1,927,256 9/1933 Copeland et al 2,353,676 7/1944 Kogl 3,168,771 2/1965 Nelson 249/50 Primary Examiner-Robert D. Baldwin Assistant Examiner-DeWalden W. Jones Attorney-Salter & Michaelson [5 7] ABSTRACT A form assembly for prefabricating a concrete structure by casting that includes an outer member and an inner member between which a cavity is defined, the inner member having expandable walls that are urged outwardly by jack elements and that are releasable to provide for removal of the inner and outer members after the structure is cast and is still curing in place.

8 Claims, 9 Drawing Figures PATENTEDBEB25 1915 3.780.976 SHZET 2 BF 3 INVENTOR 36 35 78 7 ALBERT J. MESSIER FIG.5 j

ATTORNEYS PATENTEUHEC25 ms 3; 780.976

' sum 3 [IF 3 3635 75 FIG 6 INVENTOR ALBERT J. MESSIER wim ATTORNEYS CONCRETE. FORM ASSEMBLY HAVING EXPANDABLE INNER CORE BACKGROUND OF THE INVENTION The present invention relates to the prefabrication of concrete structures such as steps, containers, tanks and the like by casting.

In the casting of a concrete structure such as steps for domestic dwellings, it has been the usual practice to pour the concrete into a mold cavity that is formed between an outer mold member and an inner mold member. Stripping of the mold in these prior known concrete structures was not usually done before the concrete cured, since there was no convenient way of removing the inner mold. Thus, it was only after the concrete was completely dry that the outer mold member was lifted by a hoist off of the concrete structure. Thereafter, the stepstructure had to be lifted by a hoist from contact with the inner mold member. It is understood that such a procedure was time consuming and.

SUMMARY OF THE INVENTION The present invention provides an arrangement wherein the mold members for forming a concrete structure can be removed from the prefabricated structure while the concrete is still curing so that the mold members can be reused in the fabrication of other concrete structures. This is accomplished by providing that the walls that define the inner mold are urged outwardly toward the walls of the outer mold, and after pouring of the concrete into the mold cavity, the inner mold walls are collapsed inwardly to release the inner mold from contact with the poured concrete.

For this purpose the inner mold includes flexible strips that interconnect the walls thereof and provide for movement of the inner mold walls relative to the poured concrete. This inward movement of the walls of the inner mold relieves the stresses on the still curing concrete thereby enabling the molds to be removed from the stoop before the concrete is completely dry and cured. Both the inner and outer molds may be provided with bottom rollers for facilitating their removal from the still curing concrete structure.

Accordingly, it is an object of the present invention to provide a form assembly for a prefabricated concrete structure that is removable from the poured concrete while it is still curing.

Another object of the invention is to provide a concrete form assembly having an expandable inner mold member that is relieved from engagement with the poured concrete structure during the curing thereof and thereafter removed with an outer mold from the concrete structure for further use.

Still another object is to provide an expandable inner mold member for use in the casting of prefabricated concrete structures, wherein the inner mold member includes walls that are connected to resilient material at the edges thereof, the resilient material enabling the walls to be urged into a first position for defining concrete receiving a mold cavity with an outer mold member and thereafter providing for release of the inner mold walls from the molding position so that the inner and outer molds can be removed from the concrete structure during the curing thereof.

Other objects,.features and advantages'of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.

DESCRIPTION OF THE DRAWINGS In the drawings which illustrate the best mode presently contemplated for carrying out the present invention:

FIG.-l is a side elevational view of the concrete form assembly embodied in the present invention;

FIG. 2 is a top plan view of the concrete form assembly illustrated in FIG. 1;

FIG. 3 is a rear elevational view of the form assembly;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 2;

FIG. 5 is a sectional view taken along line 5-5 in FIG. 4, and showing the inner mold in the expanded position;

FIG. 6 is a view similar to FIG. 5, but showing the inner mold in the collapsed position after the concrete DESCRIPTION OF THE INVENTION Referring now to the drawings and particularly to FIGS. 1 through 6, the concrete form assembly is illustrated and is generally indicated at 10.

The form assembly 10 includes an outer mold generally indicated at 11 and an inner core mold generally indicated at 12. By way of example, the molds are shaped so as to form a prefabricated step and platform structure normally used as a stoop in residential dwellings and some business establishments. It is understood however that other concrete structures such as tanks, vats, cores and the like may be formed by the subject invention without departing from the spirit thereof.

As illustrated in FIGS. 1 and 2, the outer mold 12 is assembled as a unitary construction and is defined by vertical step risers l4, horizontal step treads 16, a rear wall 18 and spaced side walls 20. The treads 16 are pivotally connected to the risers 14 by hinge assemblies 21 and are locked to the adjacent riser by slide bolts 22 that are received in U-bolts 23 secured to the risers 14. Similar slidebolts 24 are mounted on the treads l6 and are secured to U-bolts 25 fixed to brackets 26 on the side walls 20 for locking the treads 16 in place. Additional slide bolts 27 are mounted on the risers 14 and are received in spring loaded U-bolts catches 28. The catches 28 are secured to brackets 29 that are mounted on the side walls 20 to further fix the risers in place. The rear wall. 18 is also secured to the side walls 20 by slide bolts 30 received in U-bolt catches 31 that are secured to brackets 32 fixed to the side walls 20. Vertical braces 33 are welded to horizontal braces 34 and 35 and cooperate with the side walls 20 and rear wall 18 to form the outer mold 11 in the hollow configuration as illustrated.

As further seen in FIGS. 1 and 6, the lower horizontal braces 35 which are formed with an angle iron configuration have rollers 36 mounted thereon, the rollers 36 engaginga slab or platform 38 and providing for rolling movement of the outer mold as will be described hereinafter.

Referring now to FIGS. 4, 5 and 6, the inner mold 12 is illutstrated in detail and as shown includes a top wall 40 and side walls 42 that are interconnected to the top wall through flexible strips 44. Reinforcing members 46 are joined to the top and side walls 40 and 42 and receive the flexible strips 44 for securement thereto by any convenient means such as rivets, nails or screws. Referring to FIG. 4, an inclined forward portion 48 is shown joined to the top wall 40 and forms a forward extension thereof. The forward extension 48 of the top wall is also joined to the side walls 42 by the flexible strips 44 and it is seen that the top wall 40, forward extension 48 and side walls 42 may be moved relative to the walls of the outer mold 11 by reason of their interconnection through the flexible strips 44. Preferably, the flexible strips 44 are formed of a rubber material; although, it is contemplated that other resilient materials could also be used in fabricating the strips 44.

As will be described, the inner mold walls are movable relative to the outer mold walls to release the inner and outer molds from concrete structure as poured. Thus, it is seen that the walls of the inner and outer molds as spaced from each other define a cavity for receiving concrete therein. The poured concrete forms a concrete structure, which as illustrated herein, is in the form of a stoop that includes a plurality of steps and a platform. (See FIG. 9).

In order to provide for the relative movement of the walls of the inner mold 1 1, spaced gate assemblies generally indicated at 46 are provided, and as shown in FIGS. 4 and 5 each of the gate assemblies 46 includes spaced vertical braces 49 to which arejoined upper and lower horizontal braces 50. Cross braces 52 are secured to the vertical braces 49 and the horizontal braces 50 and stabilize the assembly. Fixed to the left vertical brace 49 is seen in FIG. 5, are extensions 54 through which pins 56 extend for mounting the gate assemblies 46 on brackets 58 that are joined to the left side wall 42 as seen in FIG. 5. Extensions 60 joined to the right vertical brace 49 are received on brackets 62 secured to the right side wall 42, and jacks 64 extend through the right vertical brace 49 for engagement with the brackets 62. Extending through the upper horizontal brace 50 are jacks 66 that engage the underside of the top wall 40 and inclined top wall extension 48 as seen in FIGS. 4 and 5. A forward spreader bar 68 (FIG. 7) is fixed to a bracket 70 mounted on a side wall 42 by a pin 71 and rests on a similar bracket that is secured to the opposite side wall 42. Jacks 72 extend through the spreader bar 68 and engage the underside of the inclined top wall extension 48 adjacent to the lower end thereof.

The inner mold 12 is also provided for sliding movement when it is released from the cast step structure and for this purpose includes rollers or casters 78 that are mounted on the brackets 58 that are fixed to the lowermost portion of the side walls 42. It is understood that the side walls 42, top wall 40, and forward extension 48 of the inner mold may be formed of any suitable material; although, it has been found that forming these walls of a metal material enables a cast structure to be formed that is consistent in the wall conformation thereof.

As illustrated in FIGS. 3, 5 and 6, bottom spacers 75 are joined directly to the platform 38 and space the outer mold walls 20 from the inner mold walls 42. The spacers also define a support for the structure as cast in the cavity between the inner and outer molds, and enable the cast structure to be easily lifted from the platform 38 after casting and curing. It is understood that the spacers 75 may be constructed of any suitable material, such as wood or metal.

In use of the form assembly, the outer mold 11 is lockedin position on the platform 38 by anchor bolts 74 that extend through fixed brackets 76 for engagement with the side walls 20. The inner mold 12 is located within the outer mold 11, and is also supported on the platform 38 by the rollers 78. The side walls 42 of the inner mold 12 are spaced from the side walls 20 of the outer mold 11 and the extension 48 of the top wall of the inner mold 12 is spaced from the risers l4 and treads 16 of the outer mold 11, thereby cooperating with the top wall 40 of the inner mold 12 to define a mold cavity.

Prior to pouring the concrete into the mold cavity, the jacks 64, 66 and 72 are moved outwardly to force the top wall 40, extension 48 and side walls 42 of the inner mold outwardly, the flexible strips 44 permitting the outward movement to the position illustrated in FIG. 5. The treads 16 of the outer mold 11 are pivoted upwardly with respect to the risers 14 and held in this position by engagement of hooks 77 with eye catches 79. After each section is filled with concrete, the treads 16 are lowered and secured in place by the bolts 22 and 24. The bolts 27 act to retain the risers 14 in engagement with the side walls 20 of the outer mold and the pivotal connection of the treads and risers further insure their being interlocked in place.

As illustrated in FIG. 9, the finished stoop generally indicated at 82 may include a nosing 80 that is formed around the step and platform edges. Referring to FIG. 8, the nosing 80 may be formed by reducing the thickness of the upper portion of the side walls 20 and risers 14. As the concrete is poured the nosing 80 is formed along edge of the tread and overhangs the risers and side walls of the stoop 82.

After the concrete has been poured into the mold cavity to form the concrete stoop 82 illustrated in FIG. 9, and while the concrete is curing, the jacks 64, 66 and 72 are moved inwardly and the gate assemblies 46 and spreader bar 68 are pivoted from their normal positions to thereby release the top wall extension 48 and the side walls 42 from contact with the walls of the poured concrete structure. It is seen that this return movement of the inner mold walls is insured by the resilient strips 44 which act to return to their original position once the stress has been relieved by the jacks.

With the inner mold 12 released from engagement with the poured concrete structure, the inner mold 12 can be rolled outwardly on the rollers 78, and thereafter and upon release of the anchor bolts 74, the outer mold 11 may also be removed from engagement with the poured concrete structure by rolling it outwardly on the rollers 36. The concrete stoop 80 as poured is allowed to continue curing, while the form assembly 10 may be used to cast another structure.

While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described.

What is claimed is:

1. A form assembly for casting a prefabricated concrete structure, comprising an outer mold having side walls formed thereon, an inner mold located inwardly of the outer mold and having side walls corresponding to and spaced from the side walls of said outer mold and further including a top wall, the side walls of the inner and outer molds being spaced apart to define a mold cavity therebetween, a strip flexible material being secured to and extending between the top wall and each of the side walls of said inner mold, wherein the walls of the inner mold are movable in biased relation toward the walls of the outer mold, an inner support assembly interengaging the side walls of said inner mold, and jack members mounted on said inner support assembly and being movable toward and away from the side and top walls of said inner mold, wherein the walls of said inner mold are movable by said jack members relative to the corresponding walls of said outer mold and as permitted by the flexibility of said flexible material that interconnects the walls of said inner mold, said inner support defining a gate assembly having bracing members that are interconnected to one of the side walls of the inner mold, one of said jack members that is mounted on said inner support engaging another of the side walls of said inner mold, wherein said inner mold walls are movable by said jack members relative to the walls of said outer mold.

2. A form assembly as set forth in claim 1, wherein the molds are adapted to be supported on a floor, wheel means supporting at least one of said molds for movement along the floor towards and away from the concrete structure as cast in said mold cavity.

3. A form assembly as defined in claim 2, said wheel means including rollers mounted on said inner mold and additional rollers mounted on said outer mold and providing for rolling movement thereof.

4. A form assembly as set forth in claim 1, said outer mold including a plurality of vertical risers and a plurality of treads, each of said treads being hingedly connected to a riser and being movable from a closed to an open position during the casting of said concrete structure, and means for securing said treads in a closed position after pouring and during curing of said concrete structure.

5. A form assembly for casting a prefabricated concrete structure comprising an outer mold, an inner mold located inwardly of the outer mold in spaced relation so as to define a mold cavity therebetween, said inner mold including a plurality of walls mounted for movement toward and away from the walls of the outer mold, and a strip of flexible material secured to adjacent walls of said inner mold and extending therebetween for resiliently biasing the walls of said inner mold toward the walls of the outer mold, said inner mold including a gate assembly having bracing members that are interconnected to one of the walls of the inner mold and jack means mounted on said gate assembly and en gaging another of the walls of said inner mold for moving said inner mold walls relative to the walls of the outer mold, the walls of said inner mold being defined by a pair of side walls and a top wall extending between said side walls, a strip of said flexible material being secured to and extending between said top wall and each of said side walls, means mounting one end of said gate assembly to one of said side walls, means supporting the outer end of said gate assembly on the other one of said side walls, said jack means including at least one jack mounted on said gate assembly for movement towards and away from the top wall, and one other jack mounted on said gate assembly for movement towards and away from said other side wall.

6. A form assembly as set forth in claim 5, a bracket on said other side wall which supports said other end of said gate assembly. I

7. A form assembly as set forth in claim 4, said securing means including slide bolts mounted on each of said vertical risers and treads, and catches mounted on the outer surface of the side walls of the outer mold adjacent to said slide bolts for receiving the bolts in locking relation, wherein said treads and risers are fixed in place during the curing of the concrete structure.

8. A form assembly as set forth in claim 7, additional slide bolts mounted on said treads along the front portion thereof, and catches secured to said risers adjacent ing relation. 

1. A form assembly for casting a prefabricated concrete structure, comprising an outer mold having side walls formed thereon, an inner mold located inwardly of the outer mold and having side walls corresponding to and spaced from the side walls of said outer mold and further including a top wall, the side walls of the inner and outer molds being spaced apart to define a mold cavity therebetween, a strip flexible material being secured to and extending between the top wall and each of the side walls of said inner mold, wherein the walls of the inner mold are movable in biased relation toward the walls of the outer mold, an inner support assembly interengaging the side walls of said inner mold, and jack members mounted on said inner support assembly and being movable toward and away from the side and top walls of said inner mold, wherein the walls of said inner mold are movable by said jack members relative to the corresponding walls of said outer mold and as permitted by the flexibility of said flexible material that interconnects the walls of said inner mold, said inner support defining a gate assembly having bracing members that are interconnected to one of the side walls of the inner mold, one of said jack members that is mounted on said inner support engaging another of the side walls of said inner mold, wherein said inner mold walls are movable by said jack members relative to the walls of said outer mold.
 2. A form assembly as set forth in claim 1, whereiN the molds are adapted to be supported on a floor, wheel means supporting at least one of said molds for movement along the floor towards and away from the concrete structure as cast in said mold cavity.
 3. A form assembly as defined in claim 2, said wheel means including rollers mounted on said inner mold and additional rollers mounted on said outer mold and providing for rolling movement thereof.
 4. A form assembly as set forth in claim 1, said outer mold including a plurality of vertical risers and a plurality of treads, each of said treads being hingedly connected to a riser and being movable from a closed to an open position during the casting of said concrete structure, and means for securing said treads in a closed position after pouring and during curing of said concrete structure.
 5. A form assembly for casting a prefabricated concrete structure comprising an outer mold, an inner mold located inwardly of the outer mold in spaced relation so as to define a mold cavity therebetween, said inner mold including a plurality of walls mounted for movement toward and away from the walls of the outer mold, and a strip of flexible material secured to adjacent walls of said inner mold and extending therebetween for resiliently biasing the walls of said inner mold toward the walls of the outer mold, said inner mold including a gate assembly having bracing members that are interconnected to one of the walls of the inner mold and jack means mounted on said gate assembly and engaging another of the walls of said inner mold for moving said inner mold walls relative to the walls of the outer mold, the walls of said inner mold being defined by a pair of side walls and a top wall extending between said side walls, a strip of said flexible material being secured to and extending between said top wall and each of said side walls, means mounting one end of said gate assembly to one of said side walls, means supporting the outer end of said gate assembly on the other one of said side walls, said jack means including at least one jack mounted on said gate assembly for movement towards and away from the top wall, and one other jack mounted on said gate assembly for movement towards and away from said other side wall.
 6. A form assembly as set forth in claim 5, a bracket on said other side wall which supports said other end of said gate assembly.
 7. A form assembly as set forth in claim 4, said securing means including slide bolts mounted on each of said vertical risers and treads, and catches mounted on the outer surface of the side walls of the outer mold adjacent to said slide bolts for receiving the bolts in locking relation, wherein said treads and risers are fixed in place during the curing of the concrete structure.
 8. A form assembly as set forth in claim 7, additional slide bolts mounted on said treads along the front portion thereof, and catches secured to said risers adjacent to said additional slide bolts for receiving them in locking relation. 